Process of producing hydrocyanic acid.



O. DIEFFBNBAGH & W. MOLDENHAUBR.. pocss op PRODUGING HYDROGYANIG ACID.

Patented Apr. 5, 1910.

. fn/1m @wat @ai Qqjjwdm;

@FLL r APPLGATION FILED APR. 16. lOS.

l osa-,osa

OTTO DIEFFNBACH AND WILHELM MOLDENAUER, OF DARMSTADT, @EHEIMANY.

l POCESS F PRODUCING- HYDROCYANIC ACID.

Specification of. Letters Patent.

atented Apr. 5, 1910.

Application filed April 16, 1908. Serial No. 427,407.

To all whom it may concern:

Bc it known that We, O'r'ro Dinrrnnnacir, doctor of philosophy, proiessor at the Techy nical. High ,School at Darmstadt, and lViL- HELM MOLDENHAL'ER, doctor of philosophy, lecturer at the Technical High School, both subjects of the German Emperor, and res1- .dents of Darmstadt, in the Grand Duchy of Hesse, Germany, (thepost-oftice address of (.'r'rov DInFrnN-ACH being Ohlystrasse ilo. -v

(l, that .ot lViLHELM MoLnnNi-IAUER Lucas- Weg' Nojlh) have invented new and useful Improvements in Processes of Producing is a specication. v

It'is Well known that hydrocyanic acid can be produced by passing,` a mixture of nitrogeli and hydrogen over highly heated ca-rbou, and. recent experiments have, moreproportional over, demonstrated that a yield as high as 35% can be obtained at temperatures ot about. 350()D centigrade.

For the industrial applica-tion of this process a cheap andsimplc method of producing the necessary nitrogen-hydrogen mixtureI is of the highest importance. Since the production of pure nitrogen and hydrogen, by` whatever method attained, inrolves considerable expense, the question arises whether the mixtures of the same With carbon monoxid or carbon dioxid, Whichcau be eheapl y and easily produced commer cially, are suitable for the purpose in View. From the theoretical standpoint, it Would appear that the possibility of so applying these mixtures is very small, for since hydrocyanic acid at high temperatures is capable of reacting with carbon monoxid, according to the equation:

eHcNLcozngostNmLac,

it .might certainly be expected that it would bon monoxid or that't Weuldbe destroyed by the latter immediately upon 'its formation. When it is found thatthis View is contradicted by experiment, .the only explanation possible is that thet'rapidity of the above reaction is not sutiicientlygifeat when,

under suitable experimental conditions, the

i gas-mixture is subjected to rapid''cooling, as

to permit of the decomposition of large' quantities of the hydrocyanic acid newly E 'oduced.- if, for instance, the mixture iown as y ADawson gas, which consists rapidly aspirated from the furnace, accord i ing to the degree of temperature at which the process is conducted.

The hydrocyanic acid thus produced can be employed for the production of other cyanogen compounds, or. may be transformed into ammonium .sulfate by passing it through ctmcentrated sulfuric acid. The hydrogen and nitrogen which have not undergone transformation into hydrocyanic acid together With the carbon monoXid mixed therewith may, after the removal of. the acid, be again passed over incandescent carbon for the purposevofobtaining a furlv ther yield of hydrocyanic acid', or they may be applied to heating purposes.

An apparatus for carrying. the process into practical effect is indicated in the accompanying drawing` in Which a is the gals producer (generator) into which steam and air is blown in by the inlets 6,0, while the fuel Z is introduced by a hopper e. y

The gas produced in the usual manner escapes by the conduit f and enters-the electric furnace g, which is filled with' colte 7L (by means of a hopper z').

7a and Z are carbon electrodes and m and n electric conductors Which `lead to the said electrodes.

o is a conduit by which the produced-gas is conveyed to the cooler, absorber and gas possible, for which purpose the high tem-,- yperature of the gas-mixture escaping from the converter may.' be turned to 'account by the use of suitable' regenerative apparatus.

chiefly of hydrogen, carbon monoxid, nitro-, Obviously the enriching of theDotvson gas may be .attained by means ofv hydrogen otherwise produced, or by means of water gas, just as, in general, a gas-mixture of the requisite character may be obtained by mixing Dowson gas, water-gas, producer-gas and the like in suitable Finally a greater or lesser proportion of the carbon monoxid or carbon dioxid contained in the gas mixturev can be'removed in any suitable manner prior to use. The mixture of nitrogen and hydrogen may be produced in the same apparatus as is duction of hydrocyanic acid. lf water-vapor and air are simultaneously conducted thereinto, a mixture of carbon monoxid, hydrogen and nitrogen will be first formed under the action `of the lowing carbon, whereupon the two latter will combine with the carbon furnace to form hydrocyanic acid. In'this apparatus also the enriching of the gas-mixture escaping from the Dowson gasenelrator with more hydrogen may be efectedfor whichpurpose it is only necessary to` mix the frtherniecessary quantity df water-vaporwith the gasesrbefore or after .their passage through tliegenerator. The requisite high temperature o f' the car- .bon serving tol eect the formation of the hydroc anic acid is best obtained in an'electrical 'urnace, and any form of electrical heating may be used, whether the electric arc or electrical resistance, and in the latter ,case the heating maybe either internal or external. ln the case of an arc furnace the electrodes may themselves furnishA the neckessary carbon for the formation of thehydrocyanic acid.

Example: Within a generator or producer a so called Dowson gas is produced by blowing in say 3 cubic meters ofair and 0.6 kilo steam er l llrilo carbon. The gas thus produced consists of CO 27.6 Vol. per cent.

V l c n n u l( t H 51.8 u u :c

This gas is blown into the electric arc-fur nace. When it leaves the latter it passes a cooling-device and-the absorption apparatus where the HCN maining waste gases are led to the gas container and may ne used again.

Nhen the gas passes through the electric furnace with a velocity of 10U-500 liters per prol'vortioxis.l

used for the pro-` resent in the hottest zone of the is separated, while the rel l'kilowatt per hour, a considerably concenl trated HON gas is produced. Instead of l separately producing the gas in a producer, one may introduce the above stated proportions of air and steam into the electric furnace directly.

` The expression Dowson gas used in the 'specification refers to a. gas produced according to the following formulae:

C -l- O CO (Ll-H)=COi-lrl2, starting fro1n`air and steam.

In the foregoing process the following reaction takes` place: l

We claim- 1. The process l acid by synthesis coal, hydrogen and atmospheric nitrogen, consisting in passing over. the coal a mixture of hydrogen and nitrogen kcontaining not more than forty per cent. Aof carbon oxid, substantially as described.

2. The process of producing hydrocyanic 5 acid by synthesis by means of highly heated carbon, ,hydrogen and atmospheric nitrogen, consisting in passing over the carbon a mix- Yture of hydrogen and atmospheric nitrogen containing carbon oXids, 'substantially as described. y

3. The process of producing hydrocyanic acid by synthesis by means of highly heated carbon, hydrogen and atmospheric nitrogen, consisting in passing over the carbon `a mixture of hydrogen and atmospheric nitrogen containing carbon monoxid and dioxid, substantially as described.

Il. The process of producing hydrocyanic `acid by synthesis byy means of highly heated carbon, hydrogen and atnwspheric nitrogen, consisting in passing over the carbon a miX- of producing hydrocyanic containing commerciali y produced gases 1n which carbon oxids are introduced in the desired proportions by the admixturc of other gases, substantially as described.

In testimony, that wc claim the foregoing I as our invention, we have signed our names in presence of two witnesses, this second vday olf-,April 1908.

OTTO DLEFFENBACH.

l WILHELM ll/[OLDENHAUER W itnesses KARL WEBER,

FRIEDRICH DARMSTDTEB.

by means of highly heated ture of hydrogen and atmospheric nitrogen. 

